Power management techniques for a power sensitive wireless device

ABSTRACT

Techniques are disclosed for reducing power consumption on a power sensitive wireless device, such as for example a digital wireless camera operating on a battery. According to some techniques, power can be reduced when a portable device is in close proximity to the power sensitive wireless device, such as when a person is home and the recording of video on a digital wireless security camera can be disarmed. Some techniques include filtering mechanisms, which reduce unnecessary information being transmitted to the wireless network circuit of the power sensitive wireless device. Other techniques include modifying or adapting IEEE 802.11 standards to achieve power reducing results such as for example reducing the number of times to wake up to receive the beacons. Also, improved synchronization techniques are implemented such as for example improved synchronization accuracy allows reducing the duration of the wake time for receiving the beacons.

CROSS-REFERENCE TO RELATED APPLICATIONS AND EFFECTIVE FILING DATEENTITLEMENT

This application is entitled to the benefit of and the right of priorityto U.S. Provisional Patent Application No. 62/363,784, entitled “POWERMANAGEMENT TECHNIQUES FOR POWER SENSITIVE WIRELESS DEVICE”, filed Jul.18, 2016, which is incorporated herein in its entirety by this referencethereto.

TECHNICAL FIELD

The present disclosure relates generally to electronic communications,and more specifically, to power management techniques for a powersensitive wireless device.

BACKGROUND

With the emerging technologies of wireless networks, sensor technology,and the Internet, there is an ever increasing demand for employing thesetechnologies in such a ways as to achieve inexpensive, convenient,low-maintenance, and reliable products and services for consumers. Thisis particularly relevant with wireless digital cameras that are equippedwith sensors in addition to wireless network circuits and that operateon battery power, such as for example battery-operated home securitycameras.

Accordingly, it is desirable to provide methods and apparatuses thatreduce the power consumption of the power sensitive wireless devices.

BRIEF DESCRIPTION OF THE DRAWINGS

The present embodiments are illustrated by way of example and are notintended to be limited by the figures of the accompanying drawings.

FIG. 1 is a representative computer network environment within whichsome embodiments may be implemented;

FIG. 2 is a high-level functional block diagram illustrating a powersensitive wireless device equipped with a secondary processor inaccordance with some embodiments;

FIG. 3 is a functional diagram illustrating certain implementationdetails of a specific example of changing the power state of a powersensitive device based on location of a portable device, in accordancewith some embodiments;

FIG. 4 is a flowchart illustrating a method for changing the power stateof a power sensitive device based on location of a portable device, inaccordance with some embodiments;

FIG. 5 is a timing diagram for the wireless sensor to receive beaconinformation from the acknowledgement (ACK) packet transmitted from thebase station, in accordance with some embodiments;

FIG. 6 is a timing diagram for the wireless sensor to receive from thebase station an unscheduled beacon packet after the acknowledgement(ACK) packet has been transmitted, in accordance with some embodiments;

FIG. 7 is a timing diagram for determining an estimate of the clockdrift to use in reducing synchronization calculations, in accordancewith some embodiments;

FIG. 8 is a flowchart illustrating a method for determining an estimateof the frequency drift to use in reducing synchronization calculations,in accordance with some embodiments;

FIG. 9 is a high-level functional block diagram illustrating IEEE 1588synchronization, which can be implemented by the base station, inaccordance with some embodiments;

FIG. 10 is a diagram illustrating a precision time protocol defined inIEEE 1588, which can be implemented by the base station, in accordancewith some embodiments;

FIG. 11 is an example diagram illustrating the starting and stopping ofa monitoring process based on whether a person is in or outside ageo-fence in accordance with some embodiments;

FIG. 12 is an example diagram illustrating three different power statescorresponding to three different motional statuses, in accordance withsome embodiments;

FIG. 13 is an example diagram illustrating a geo-fence drawn on a map,in accordance with some embodiments;

FIG. 14 is an example diagram illustrating a sequence of locations basedon how the user with the portable device application moves, inaccordance with some embodiments;

FIG. 15 is an example diagram illustrating a remote cellularcommunication system sending a location change detection message to theremote server, in accordance with some embodiments;

FIG. 16 is an example diagram illustrating cellular tower triangulationfor recognizing the location of the portable device, in accordance withsome embodiments;

FIG. 17 is an example diagram illustrating a cellular tower and theranges and sectors from the tower, in accordance with some embodiments;

Like reference numerals refer to corresponding parts throughout thefigures and specification.

DETAILED DESCRIPTION

Techniques are disclosed for reducing power consumption on a powersensitive wireless device, such as for example a digital wireless cameraoperating on a battery and operating in a wireless local area network(WLAN) system. For purposes of understanding herein, a power sensitivewireless device is a wireless device that relies on a power source thathas a limited amount of power, such as a battery. According to sometechniques, power consumption can be reduced when a portable device isin close proximity to the WLAN system, a user-defined geo-fence, or thepower sensitive wireless device. For example, when a person is home, therecording of video on a digital wireless security camera can bedisarmed. Some techniques include filtering mechanisms, which reduceunnecessary information being transmitted to the wireless networkcircuit of the power sensitive wireless device. Other techniques includemodifying or adapting IEEE 802.11 standards to achieve power reducingresults such as for example reducing the number of times to wake up toreceive the beacons. Also, improved synchronization techniques areimplemented such as for example improved synchronization accuracy allowsreducing the duration of the wake time for receiving the beacons.

Among other benefits, the embodiments disclosed herein can increasebattery life and reduce the power consumption of power sensitivewireless device by providing a variety of techniques that can beperformed individually or in combination in a way achieves the same orbetter performance, but without unnecessary power consumption.

In the following description, numerous specific details are set forthsuch as examples of specific components, circuits, and processes toprovide a thorough understanding of the present disclosure. Also, in thefollowing description and for purposes of explanation, specificnomenclature is set forth to provide a thorough understanding of thepresent embodiments. However, it will be apparent to one skilled in theart that these specific details may not be required to practice thepresent embodiments. In other instances, well-known circuits and devicesare shown in block diagram form to avoid obscuring the presentdisclosure.

The term “coupled” as used herein means connected directly to orconnected through one or more intervening components or circuits. Any ofthe signals provided over various buses described herein may betime-multiplexed with other signals and provided over one or more commonbuses. In addition, the interconnection between circuit elements orsoftware blocks may be shown as buses or as single signal lines. Each ofthe buses may alternatively be a single signal line, and each of thesingle signal lines may alternatively be buses, and a single line or busmight represent any one or more of a myriad of physical or logicalmechanisms for communication (e.g., a network) between components. Thepresent embodiments are not to be construed as limited to specificexamples described herein but rather to include within their scope allembodiments defined by the appended claims.

System Overview

FIG. 1 is a representative computer network environment 100 within whichsome embodiments may be implemented. The environment 100 includes a basestation 110, a remote server over a network 130, and a plurality ofpower sensitive wireless devices 120 (“power sensitive device”), whereone such device is shown.

The base station 110, which is illustrated as operating in “access point(AP)” mode for a camera, is coupled together with the remote server 130such that the base station 110 can enable power sensitive devices 120 toexchange data to and from the remote server 130. In some embodiments,the base station 110 and the remote server 130 may be connectedwirelessly (e.g., which may include employing an IEEE 802.11 wirelessnetwork, or a data traffic network based on wireless telephony servicessuch as 3G, 3.5G, 4G Long-Term Evolution (LTE) and the like). Thetechnologies supporting the communications between the base station 110and the remote server 130 may include Ethernet (e.g., as described inIEEE 802.3 family of standards) and/or other suitable types of areanetwork technologies, such as competing or alternative standards to theIEEE 802.11 family of standards (e.g., WiMAX). Examples of differentwireless protocols in the IEEE 802.11 family of standards can includeIEEE 802.11a, IEEE 802.11b, IEEE 802.11n, IEEE 802.11ac, IEEE 802.11af,IEEE 802.11ah, and IEEE 802.11ad.

Although not shown for simplicity, the base station 110 may include oneor more processors, which may be general-purpose processors or may beapplication-specific integrated circuitry that provides arithmetic andcontrol functions to implement the techniques disclosed herein on thebase station 110. The processor(s) may include a cache memory (not shownfor simplicity) as well as other memories (e.g., a main memory, and/ornon-volatile memory such as a hard-disk drive or solid-state drive). Insome examples, cache memory is implemented using SRAM, main memory isimplemented using DRAM, and non-volatile memory is implemented usingFlash memory or one or more magnetic disk drives. According to someembodiments, the memories may include one or more memory chips ormodules, and the processor(s) on the base station 110 may execute aplurality of instructions or program codes that are stored in itsmemory.

The power sensitive devices 120 can connect to and communicate with thebase station 110 wirelessly including, for example, using the IEEE802.11 family of standards (e.g., Wireless LAN) and/or other suitabletypes of area network technologies, such as competing or alternativestandards to the IEEE 802.11 family of standards (e.g., WiMAX), and caninclude any suitable intervening wireless network devices including, forexample, base stations, routers, gateways, hubs, or the like. Dependingon the embodiments, the network technology connecting between the powersensitive devices 120 and the base station 110 can include othersuitable wireless standards such as the well-known Bluetoothcommunication protocols or near field communication (NFC) protocols. Insome embodiments, the network technology between the devices 120 andstation 110 can include a customized version of WLAN, Bluetooth, orcustomized versions of other suitable wireless technologies. Powersensitive devices 120 can be any suitable network-connected cameras (or“IP cameras”). It is contemplated that additional examples of thedevices 120 equipped with video and audio recording technology caninclude computing or mobile devices including, for example, smartphones,tablet computers, laptops, personal digital assistants (PDAs), or thelike. Additional examples of the devices 120 can include home sensors(e.g., motion detection sensors and temperature sensors) that canconnect to the Internet).

It is noted that one of ordinary skill in the art will understand thatthe components of FIG. 1 are just one implementation of the computernetwork environment within which present embodiments may be implemented,and the various alternative embodiments are within the scope of thepresent embodiments. For example, the environment 100 may furtherinclude intervening devices (e.g., switches, routers, hubs, etc.) amongthe base station 110, the remote server 130, and the power sensitivedevices 120. In some examples, the network (shown as signal lines) overwhich the base station 110, the power sensitive devices 120, and theremote server 130 connect comprises the Internet.

Multi-Tier Wake on Wireless LAN

In designs of power sensitive wireless devices, the main processor ofthe device may be sleeping most of the time and may be woken up usingtechnologies, such as Wake on wireless LAN, which allows the remotewake-up of the device (e.g., such as camera 120) from a standby powerstate or power save mode for performing device related operations. Ithas been found that there are a multitude of multicast broadcast packetswhich arrive at the power sensitive device, yet which should not wake upthe main processor. Further, there are many packets which the powersensitive device may need to process but do not require the processingpower of the main processor. Thus, there is no need to wake up the mainprocessor for these types of packets. These and other situations aredescribed in detail below.

FIG. 2 is a high-level functional block diagram 200 illustrating a powersensitive wireless device equipped with a secondary processor inaccordance with some embodiments. As shown in FIG. 2, the powersensitive wireless device includes a main processor 210, a wirelessnetwork circuit 220, a secondary processor 230, a motion sensor 240, andother modules 260 (e.g., a camera). In accordance with one or moreembodiments, the components are coupled to each other or interface witheach other through a bus 250.

It has been found that access points (APs) commonly forward manymulticast and broadcast transmissions originating from different sourcedinterfaces to the wireless network circuit interface. Many packets ofsuch transmissions do not need to be heard by the power sensitivewireless device, such as power sensitive device 120. For the powersensitive device 120 to process these unnecessary packets consumes muchof the power sensitive device's power. For instance, the multicastpackets can be the result of the discovery phase of application levelprotocols. Examples of such protocol include:

Universal Plug and Play;

Bonjour;

Multicast Domain Name System (MDNS); and

Discovery And Launch (DIAL) protocol.

It has been found that most power sensitive devices do not need to hearsuch packets, e.g., as described above. Also, there can be multicastpackets as result of Dynamic Host Configuration Protocol (DHCP) orAddress Resolution Protocol (ARP). Indeed, there are some types ofpackets that do not require the main processor 210 to process. Forexample, in executing applications on devices such as cameras, cellphones, and personal computers (PCs), the main processor is designed toperform intensive processing at the level of many million instructionsper second (MIPS). Thus, it is very inefficient for the main processor210 to wake up and come out of any power saving state or mode forunnecessary wireless network circuit events. In some embodiments, aswill be described in further detail below, such packets can be handledby a processor that is not required to be as powerful the main processor210 and that therefore need the main processor 210 to wake up. Thepackets which the power sensitive device may not need to hear or processcan be different from application to application. Some exemplary packetsare as follows:

Periodic 802.11 packets from a keep-alive connection, which is a singleconnection for sending and receiving HTTP requests/responses instead ofopening a new connection for each request/response pair;

Periodic ARP, DHCP, or other TCP/IP packets; and

Periodic status reports for different use cases.

In some embodiments, to save power at the power sensitive wirelessdevice 120, some of the upper layer stack (e.g., layer 3, layer 4, orapplication layer), which may have power implications, can be moved tothe wireless network circuit 220 or any processor that requires orconsumes less power than the main processor 210, as described in furtherdetail below. In some embodiments, a second processor, such as thesecondary processor 230, which is a lower power processor than the mainprocessor 210, is added to the power sensitive device 120, alsodescribed in further detail below. It should be noted that moving upperlayer stack processes to the wireless network circuit 220 and adding asecondary processor 230 can be implemented individually in someembodiments or combined in other embodiments. It should further be notedthat causing the upper layer stack to be moved to the wireless networkcircuit 220 or to a second processor can be originated at the basestation 110 or at the remote server 130 or any combination thereof.

In some embodiments, a processor is added to the power sensitive device,e.g., the secondary processor 230. The secondary processor 230 has aninterface to both the network circuit 220 and the main processor 210.Further, the secondary processor 230 processes packets, itself, and alsois configured to decide which packets do not need the main processor 210to wake up based on certain criteria, such as whether the packetrepresents a wireless network circuit event. Thus, in some embodiments,the wireless network circuit 220 can be configured to, upon receivingthe packets, decide which packets to send to the main processor 210 andwhich packets to send to the secondary processor 230.

In some embodiments, the main processor 210 is configured to learn whichpackets are unnecessary, such as for example, employing machine learningalgorithms. As the main processor 210 learns which packets areunnecessary, the main processor 210 may be further configured tocommunicate that knowledge to the network circuit 220 or to thesecondary processor 230. For instance, the unnecessary packet can beadded to a table of unnecessary packets and such table can be sent fromthe main processor 220 to either or both of the network circuit 220 andthe secondary processor 230.

In accordance with other embodiments, some of the processing that doesnot require to be performed on the main processor 220 can be integratedin to a processor that is already available. It has been observed thatsome wireless network circuits, such as the network circuit 220,integrate Advanced RISC Machines (ARM) processors (“ARM cores”) foroffloading of drivers, which typically are run on the main processor210. These ARM cores may have enough processing power to process thepackets that do not need to main processor 210 to wake up. Typically,the network circuit 220 operates on layers up to layer 2 and leaves thehigher layers for the main processor 220 to process. However, someembodiments include moving some of the upper layer processing whichmakes the main processor 210 wake up unnecessarily to the offloadprocessors of the network circuit 220.

Changing Power State of Power Sensitive Wireless Device Based onLocation of a Portable Device

To manage the power consumption of a power sensitive device, it isbeneficial for such device to have different power settings based on theneeds of a select user (“user”) of the device or based on any otherdesirability, at the moment. A select user can be, for example, an owneror an administrator of the WLAN system. A method of designating such aselect user can be, for example, the user using a software application(e.g., a mobile application) running on a user's mobile device andlogging in as a select user. The list of the select users can beidentified by suitable ways including, for example, the administrator ofthe system making such designation in cloud server (e.g., remote server130), or by logging onto an administrator's configuration page of thebase station of the wireless network system 110. For example, a securitycamera system can need a different power setting based on whether theuser(s) is home (and the security camera system can be disarmed or havea lower engagement, for instance) or whether the user(s) is outside ofthe home (and the security camera system needs to be fully or close tofully operational).

In some embodiments, the power setting and state of the power sensitivedevice can be changed based on checking the WLAN association of theportable device that user may be using (e.g., a smartphone or a tabletcomputer), discussed in further detail below. In some embodiments, thepower setting and state of the power sensitive device can be changedbased on the Global Positioning System (GPS) location of the portabledevice, also discussed in further detail below. It should be noted thatthe power settings of the power sensitive device that may be modified inaccordance with embodiments include the wireless power state, thewireless wake up period, sensory related settings, or main processor(e.g., central processing unit (CPU)) settings.

With regard to the wireless-related settings of the wireless networkcircuit 220, it is known that such network circuit can be in differentpower states. In particular, when the wireless network circuit 220 ofthe power sensitive device 120 is in sleep mode, the network circuit 220periodically wakes up to receive a beacon, e.g., the delivery trafficindication message (DTIM) beacon. The DTIM beacon is a beacon that isbroadcast typically from an AP to a device that uses power-save mode andthat contains an interval setting (e.g., DTIM) for the beacon delivery.A DTIM is a type of traffic indication map (TIM), which indicates to aclient about the presence of buffered multicast/broadcast data on theaccess point. Thus, in accordance with this technology, when the networkcircuit of the power sensitive device is in sleep mode, the networkcircuit periodically wakes up to receive the beacon, e.g., the DTIMbeacon. Typically, the period in which the network circuit wakes up iscontrolled by the AP. The AP can change the DTIM for a subset ofcommunicatively coupled power sensitive devices based on the delayrequirement (e.g., based on traffic requirements and to avoidtransmission collisions in the network). The delay requirement maydifferent if user is home or outside of the home. Thus, in accordancewith some embodiments, the AP can be configured to change the timing fora DTIM for the power sensitive device based on the specific delayrequirement in real-time received from the power sensitive device. In anembodiment, the timing is changed further based on the result ofdetecting, by the base station in the WLAN system, whether the selectuser is within a predetermined physical proximity to the WLAN system.

In some embodiments, to save the power consumption of the powersensitive device 120, the power sensitive device 120 and the basestation 110 are each configured to use or coordinate in an extendedsleep mode, such as for example wireless network management (WNM)-Sleepmode as defined in IEEE 802.11 family of standards (e.g., 802.11v),based the result of detecting the location of the portable device 130.For purposes herein, WNM-sleep mode is an extended power-save mode forthe power sensitive device 120, where the power sensitive device 120 isnot required to listen for every DTIM beacon frame and is not requiredto perform other network related updates. Thus, in accordance with someembodiments, the extended sleep mode enables the power sensitive device120 to signal to the base station 110 (or any AP) that is will be insleep mode for an extended period of time. While in extended sleep mode,the power sensitive device 120 continues to be associated with the basestation 110, yet is not required to receive or send packets from and tothe base station 110. It should be noted that in some embodiments,extended sleep mode can be used in combination with location basedwireless setting change without AP involvement.

In some embodiments, the settings of sensors can be modified based onlocation of the user or (e.g., location of the portable device). Forexample, camera settings, such as the frame rate and/or the compressionratio of the camera on the power sensitive device, can be modified basedon location of user or the portable device, as discussed in detailbelow. As well, motion detector settings can be modified when people arein home (also discussed in further detail below). For example, themotion detector can be disabled or the motion detector sensitivity canbe changed, both based on detected location criteria of the user orportable device. As another example, the frequency with which thepassive infra-red sensor of the motion detector is monitored can bechanged. In the case of array sensors, such as infrared array sensors,the number of array sensors can be reduced, in addition to reducing thesampling frequency to save power, according to some embodiments. Forexample, responsive to the result of detecting that a select user iswithin a predetermined physical proximity to the WLAN system, the powersensitive device can change a sampling frequency that the powersensitive device monitors of a passive infrared sensor. As anotherexample, responsive to the result of detecting that a select user iswithin a predetermined physical proximity to the WLAN system, the powersensitive device can change a number of sensors that the power sensitivedevice monitors in an infrared sensor.

In some embodiments, the power settings of the power sensitive device120 can be changed based on location (e.g., the location of a portabledevice of the user). Embodiments of the innovation can be understoodwith reference to FIG. 3. FIG. 3 is a functional diagram 300illustrating certain implementation details of a specific example ofchanging the power state of a power sensitive device based on locationof a portable device, in accordance with some embodiments. As mentionedabove, in some embodiments, location may be detected using GPS and theapplication that is run on the portable device 340 of the user, which isused, for example, for monitoring the sensors of the security camerasystem. For example, the detecting can be based on a location of theselect user as reported by a global positioning system (GPS) of aportable device of the select user.

Other various embodiments for detecting location are contemplated, asfollows. In accordance with some embodiments, the application on theportable device 340 is communicatively coupled to the remote server 130(e.g., the cloud). As well, the remote server 130 can communicate withthe power sensitive device 120 directly or can communicate with theresidential (e.g., home) gateway or home AP 350 or sensor gateway (notshown) to change the power setting of the power sensitive device 120. Inother embodiments, the portable device 340 when appropriately configuredcan directly communicate with the sensor gateway (not shown), the homeAP 350, or sensor AP (not shown). In other embodiments, the portabledevice 340 can be configured to communicate directly with the powersensitive device 120. In other embodiments, the network circuitconnection of the portable device 340 belonging to the user of systemcan be detected to the home AP or home gateway 350. In this case, thehome or sensor gateway 350 instructs the power sensitive device 120 tochange power settings. In some embodiments, a multicast discoverymechanism can be used to detect that a low power device such as theportable device 340 is within the home network (e.g., associated withthe home AP 350) and the mechanism can instruct the power sensitivedevice 120 to change its power setting. In some embodiments, LTE relatedlocation information are used to detect the vicinity of the powersensitive device 120 and the portable device 340. For example, thedetecting is based on Long-Term Evolution (LTE) related information froma portable device of the select user. Based on such detection,instructions can be sent to the power sensitive device 120 for changingthe power settings. In other embodiments, the telephone applicationinterface may be used by the user to indicate that the user desires tochange the power settings of the power sensitive device 120. Forexample, upon coming home, the user may open the security cameraapplication on his or her cell phone and enter information indicating tochange put the camera into extended sleep mode. As another example, thepower sensitive device can receive from an application on the portabledevice of the select user, a user instruction to manually change a powersetting of the power sensitive device. In another embodiment, the motiondetectors on the power sensitive device 120 can trigger and startrecording. It can be detected that the motion is occurring ratherfrequently and tripping the camera often based on threshold criteriasuch as a maximum number of trigger events in a predetermined interval.The user can be asked to confirm whether he or she is at the premises.For example, the number of triggering of the motion sensor can get sendfrom the power sensitive device 120 via the base station 110 for arrivalat the remote server 130. The remote server 130 can be configured todetermine that the threshold of number of motion detection triggers hasbeen exceed and can send a message intended for the application on theuser's cell phone to alert the user. For instance, the message can askthe user to confirm that he or she is, indeed, home. Then, upon learningthat the user is home, the remote server 130 can instruct the powersensitive device 120 via the base station 110 to disarm and go into lowpower mode or sleep mode to save battery power.

It should be noted that any of the location detection techniquesdisclosed above can be used singly or in combination. For example, oneembodiment may allow location detection by GPS and the application onthe portable device 340, in addition to multicast discovery. Forexample, the detecting can be based on a multicast discovery mechanismof the WLAN.

Some embodiments can be understood with reference to FIG. 4, a flowchartillustrating a method for changing the power state of the powersensitive device 120 based on the location of the portable device 340.As mentioned above, the location of the portable device 350 of the usercan be periodically monitored or checked (410) using various mechanismssuch as GPS, multicast, and so forth. When the method determines thatthe user is not home (420), e.g., using GPS determined that the portabledevice 350 is not close to the power sensitive device 120, then themethod waits for a predetermined amount of time (430) before checkinglocation again (410). When the method determines that the user is athome (420), e.g., using GPS determined that the portable device 350 iswithin a certain proximity to a designated area (e.g., within acommunication range of the base station, within a geo-fence (furtherdiscussed below), and/or in some examples, the power sensitive device120 itself), then the method causes (e.g., by sending instructions) thepower sensitive device 120 to change the power settings (e.g., wake fromsleep mode), after which the method again waits for a predeterminedamount of time (450) before checking location again (410).

In some embodiments, location detection mechanisms employ a geo-fencingtechnique for implementing the power saving techniques introduced here.The geo-fencing technique allows a user to define a geo-fence (that is,a virtual fence with a perimeter defined by the user based on a numberof specified geographic points). In some examples, such as a factorydefault mode for the base station, the geo-fence can be set as simply asa predetermined physical proximity to the WLAN system and/or the powersensitive device 120, such as introduced above. Additionally oralternatively, some embodiments provide that the remote server and/or asoftware application (e.g., a “mobile app”) may employ a graphic userinterface (e.g., to display an interactive map) to allow an authorizeduser (e.g., an owner or an administrator) to enter and define ageo-fence that he or she sees fit, so as to have a customizable area heor she wants the system to monitor (e.g., for security purposes and/orfor deploying the power saving techniques introduced here). Geo-fencingcan enable remote monitoring of an entity at a specific location (e.g.,a home) surrounded by a virtual fence (e.g., geo-fence), and automaticdetections of the user being in or out of the geo-fence. As a result,for example, the system can be configured to start or stop trackingmobile objects within the area of the geo-fence, depending on whetherthe user is in or out of the geo-fence. For example, the system maystart tracking a designated user's mobile device when it is outside thegeo-fence. Furthermore, in some embodiments, the power state of thepower sensitive device can change by tracking the location of theportable device (e.g., a cell phone) that is equipped with the clientapplication and making decisions with respect to a geo-fence. Forexample, when the camera is armed (e.g., is in monitoring mode) thesystem can be configured to wake up the camera(s) more often and/orreduce the DTIM interval. For example, FIG. 11 illustrates the startingand stopping of a monitoring process based on whether a person is in oroutside a geo-fence.

In some embodiments, the power state of the power sensitive device canbe changed by a motional status change. An embodiment can be understoodwith reference to FIG. 12, an example diagram illustrating threedifferent power states corresponding to three different motionalstatuses (e.g., arriving, dwelling, and leaving). In the example shownin FIG. 12, when the user with the portable device arrives at thegeo-fence, the power sensitive device changes the power state of thepower sensitive device to power state 2, based on the automaticdetection of the user arriving at the geo-fence. As the user remainswithin the geo-fence for a predetermined minimum amount of time (e.g.,dwelling), the power sensitive device automatically changes the powerstate to power state 3. As the user departs from the geo-fence, thepower sensitive device changes the power state of the power sensitivedevice to power state 1, based on the automatic detection of the userwith the portable device leaving the geo-fence. For example, the powersetting can include a first profile, a second profile where the powerconsumption is greater than that of the first profile, and a thirdprofile where the power consumption is greater than that of the secondprofile.

In some embodiments, determining the appropriate power setting for thepower sensitive device includes comparing a historic location of theportable device to determine the motional status. Then, the appropriatepower setting is adjusted based on the motional status. The historiclocation can be derived from machine learning techniques, where datarepresenting the location of the user/portable device is collected overtime and statistical learning techniques are applied to such data toidentify patterns.

Some embodiments can be understood with reference to FIG. 13, an examplediagram illustrating a geo-fence drawn on a map. The user can define ageo-fence over a large geographical area via the remote server or byusing the application on the portable device, for example. The remoteserver and/or the application provide a suitable user-interface for theuser to specify the parameters of the geo-fence.

Some embodiments can be understood with reference to FIG. 14, an examplediagram illustrating a sequence of locations based on how the user withthe portable device application moves. The power state of the powersensitive device may be changed based on the sequence of locations. Asan example and with reference to FIG. 14, the user is detected in afirst geo-fence (e.g., location 1: an office parking lot), proceeds to asecond location (e.g., location 2: a round-about which is near a markedlocation of interest), proceeds to a third location in a differentgeo-fence (e.g., location 3: a gas station), and proceed onward (e.g.,location 4: the user departs the geo-fence). From this pattern ofdetected locations, it can be determined from pattern recognition (e.g.,more likely than not or exceeding a certain probability) that the useris heading home (or approaching a selected geo-fence or another selectedmonitoring point) and to change the power setting on the power sensitivedevice (e.g., put the device in sleep mode).

Some embodiments can be understood with reference to FIG. 15, an examplediagram illustrating a remote cellular communication system sending alocation change detection message to the remote server. Radio signalmeasurements are received from the portable device at base stations of athird party. The third party can estimate the location of the portabledevice and communicate that location and any subsequent changes of thelocation to the remote server over a communications network (e.g., theInternet). The remote server has an appropriate interface to thecommunications network for receiving the location of the portabledevice. Upon receiving the location detection data, the remote servercan proceed to change the power settings of the power sensitive deviceindirectly as described in this disclosure.

In some embodiments, cellular tower triangulation is used forrecognizing the location of the portable device, as illustrated in FIG.16. Triangulation is a process by which the location of the radiotransmitter of the portable device can be determined by measuring eitherthe radial distance, or the direction, of the received signal from twoor three different points. FIG. 17 is an example diagram illustrating acellular tower and the ranges and sectors from the tower, in accordancewith some embodiments;

Using 802.11 for Power Sensitive Wireless Sensors

It is commonly known that the network circuit protocol, 802.11, isavailable on most home devices with wireless Internet access. Thisprotocol is available on most devices with wireless Internet access. Inaddition, this protocol is an available technology to use for powersensitive wireless sensors, including, for example:

door sensors;

window sensors;

temperature sensors;

(infrared) IR motion detection sensors; and

other power sensitive wireless sensors for which a battery may last formany months or years.

However, it has been found that 802.11 power consumption can be too highfor those type of sensors, meaning the power consumed does not correlateto the operation of the sensor. As mentioned above, an example is wakingup the main processor 210 for a network circuit event that does notrequire the power of the main processor 210 to be processed.

In some embodiments, standard 802.11 n/ac/b/g protocols are modified tooperate a lower power sensor, such as the network circuit 220, in a waysimilar to sensors using 802.15.4 based protocols (e.g., Zigbee, Zwave,or Bluetooth). A lower power sensor in this case is a sensor thatrequires less power to operate than the main processor of the system athand. While 802.11ah may provide some solutions to requiring less powerto be consumed by the power sensitive device 120, such protocol may notbe readily available and, additionally, the protocol may not provideenough functionality.

In some embodiments, the network circuit 220 behaves as an 802.11 sensorthat is not dependent on receiving the beacon. Instead, the networkcircuit 220 initiates the communication and asks for appropriateinformation from the AP (e.g., base station 110). An example of theappropriate information requested by the network circuit 220 include thetraffic indication map (TIM) from which the network circuit 220 candetermine whether the AP has any buffered frames present for it. Asanother example, embodiments adopts modified IEEE 802.11 standards suchthat a dependency on beacon reception for maintaining connection withthe power sensitive device becomes reduced or removed.

Also, in some embodiments, to reduce power consumption, the networkcircuit 220 can ask the AP for timing synchronization data on anas-needed basis. For example, in the security wireless cameraenvironment, the network circuit 220 can send data to the base station110 when it has data (e.g., video to upload to the remote server 130)and can indicate to the base station 110 during sending the data that itis looking for a TIM in a special beacon for that network circuit 220.The power sensitive device hosting the network circuit (e.g., the powersensitive wireless device 120) stays awake after it sends such data andthe AP (e.g., the base station 110) knows to send the packets rightafter having received the data. In other embodiments, with regard tosynchronization between the power sensitive device 120 and the basestation 110, the base station 110 can integrate the TimingSynchronization Function (TSF) into the acknowledgement (ACK) downlinkdata packet. Employing TSF to achieve timing synchronization is wellknown in the art and does not need to be described herein. It should benoted that in some embodiments, the AP can be configured to send packetssolely for synchronization with the power sensitive device 120.

In other embodiments, to reduce the power consumption of the powersensitive device 120, device 120 is configured to rely on the AP toencapsulate the packets in IP and send such encapsulated packets to theappropriate destinations, such as for example, the remote server 130. Insome embodiments, the AP assigns the IP address to the client andperforms the encapsulation on behalf of the power sensitive device 120.For example, the base station 110 can assign the IP address to the powersensitive device 120 and can encapsulate the packets representing thevideo which the power sensitive device 120 captured and transmitted tothe base station 110. As well, the AP can perform the standard wirelessrelated protocols, such as TCP/IP or UDP/IP, which the client may needto communicate to other devices within a predetermined vicinity (e.g.,within the home) or to devices outside. In some cases, the powersensitive device 120 may need to use the Internet Protocol (IP). To savepower consumption, the device 120 can be configured to use IP headercompressions defined for sensors. Using IP header compression reducesoverall byte count, which reduces the number of bytes to be sent orreceived, which saves power. In another embodiment, the power sensitivedevice 120 may obtain the IP address and then store such IP address fora predetermined length of time, which reduces power by not having tohave the IP address retransmitted. In other embodiments, the powersensitive device 120 may calculate the IP address based on informationpreviously stored in the device 120 or based on a hash function ofinformation that is unique to such device.

In some embodiments, the power sensitive device 120 expects to receivean unscheduled beacon as opposed to receiving periodically sent beacons.Here, the device can wake up at a predetermined time or at a timedepending on criteria and receive a beacon. According to someembodiments, the power sensitive device 120 is configured to decidewhether to use the TIM information that is embedded in the beacon and tocome out of power save. In other embodiments, the power sensitive device120 can be configured to come out of power save at a predetermined,regular schedule. Or, in other embodiments, the power sensitive device120 can be configured to come out of or go into power save in accordancewith a schedule that is based on a detected battery state of the device120. For example, if the battery state goes below a threshold, the powersensitive device 120 can go into power save mode. In other embodiments,the wake up behavior (e.g., DTIM) can be communicated to the device 120by integrating appropriate information into a corresponding fielddefined in the beacon, ACK packet or management packet.

Embodiments of the innovation can be understood with reference to FIG.5, a timing diagram 500 for the wireless sensor to receive beaconinformation from the acknowledgement (ACK) packet transmitted from thebase station. The sensor (e.g., a battery-operated wireless camera)awakes. For example, it may have received a motion trigger from themotion detection sensor to cause the camera to begin recording videodata. At some point after awaking, the sensor sends data to the AP(e.g., the base station). Upon receiving the data, the AP sends to thesensor an acknowledgement (ACK) where additional information has beenadded to the ACK. Examples of such added information include: TSF, DTIM,TIM, and other relevant beacon information.

Embodiments of the innovation can be understood with reference to FIG.6, a timing diagram for the wireless sensor to receive from the basestation an unscheduled beacon packet after the acknowledgement (ACK)packet has been transmitted. In this example, the sensor (e.g., abattery-operated wireless camera) awakes and, as in FIG. 5, sends datato the AP (e.g., the base station). Upon receiving the data, the APsends to the sensor an acknowledgement (ACK). The AP is configured tosend a beacon for this particular sensor after having sent an ACK tosuch sensor. On the sensor side, the sensor is configured to stay awakefor a predetermined time after having sent data to ensure that it staysawake long enough to receive any beacons coming from the AP. The beaconcontains standard beacon-related information for the sensor, such ascriteria for the sensor to go in to and out of wake up mode. Afterhaving received the beacon, the sensor adjusts its power settingsaccordingly. For example, after having sent video recordings to the basestation 110, the power sensitive device 120 may receive information viathe beacon to go into sleep mode. For instance, the remote server 130may have received an instruction from the user that recording of videoby the camera is not needed at this time, which causes the remote server130 to send via the beacon instructions for the camera to go into sleepmode.

In some embodiments, the power consumption of the power sensitive device120 is reduced by the AP 110 being configured to improve managingcommunication from the AP 110 to the power sensitive device 120 one waythe AP 110 is configured is to keep packets for the power sensitivedevice 120 longer than for other 802.11 device, in accordance with someembodiments. The AP 110 can then send the packets in a singleaggregation send, rather than cause the power sensitive device 120 toconsume power when received packets over multiple transmissions. Inregard to keeping packets intended for the power sensitive device 120,the AP 110 can be configured with the either of the followingparameters:

No timeout; or

A predetermined very long timeout (e.g., a predetermined timeout that islonger than what is provided in IEEE 802.11 family of standards).

Similar as to what was previously discussed, the AP 110 may use the ACK,beacon, or any other communication that the AP 110 or power sensitivedevice 120 initiated to integrate the information it wants to send tothe power sensitive device 120 or to indicate or to suggest to the powersensitive device 120 that such device is required to come out of itscurrent low power state, in accordance with some embodiments.Subsequently, when the power sensitive device 120 is out of low powerstate, the AP 110 ensures, based on certain criteria such as theidentification of the power sensitive device 120, that the packets ofthe power sensitive device 120 are assigned the highest priority or oneof the highest priorities over some packets destined for other wirelessdevices. For instance, in some embodiments, existing queues can becleared by the AP 110 causing packets of the power sensitive device 120to transmit faster than when not having priority. This technique reducespower consumption by reducing the number of transmissions for thepackets destined to the power sensitive device 120.

Embodiments include other techniques for the AP 110 to employ, asfollows. In some embodiments, a separate queue may be created by the AP110 for the power sensitive device 120. In yet other embodiments,beacon, management, or some other type of higher priority queue may beestablished and used for the power sensitive device 120. In yet otherembodiments, certain 802.11 parameters, (e.g., backoff procedure andenergy detect (ED)) can be ignored or can be assigned to the mostaggressive numbers for the downlink packets, which go out to the powersensitive device 120 once the power sensitive device 120 is out of thepower saving state. For example, the AP 110 can be configured such thatShort Inter-Frame Space (SIFS) and PCF Interframe Space (PIFS) may beused as backoff procedures waiting for an idle channel, and the ED maybe increased to higher numbers. In this way, power consumption isreduced by ignoring packets or by sending the packets out sooner. Forexample, typically the AP 110 abides by a counter, which typicallyassigned a random number between zero and 15. In an exampleimplementation, the AP can choose a number between zero and four, e.g.,a more aggressive assignment such that these packets, which are short asthey contain one byte of information, go out quicker. An example of EDbeing increased to higher numbers is as follows. Some embodimentsinclude an energy level threshold such that if the detected energy of achannel is higher than the threshold, then the channel is consideredbusy. Thus, by increasing the threshold for power sensitive devices,because the packets are short, there is a good likelihood that thetransmission will be successful. It is noted that even if thetransmission is not successful, because the packet size is short, theretransmission also has a high likelihood of being successfullytransmitted.

To save power consumption on the power sensitive device 120, someembodiments provide different rate controls for either the powersensitive device 120, the AP 110, or both. One reason to set differentrate controls is because it is contemplated that because the powersensitive device does not receive or send many packets, common ratecontrol mechanisms of the art may not have enough packets from which tolearn. Another reason is that because the sensor sends one byte of data,some embodiments enable using a lower or the lowest data rate for suchpackets or having the default rate be a fixed low rate. However, assumethere is a request to upgrade some software on the sensor, then there ismuch more data being sent to the sensor. Thus, according to someembodiments, the data rate is increased (e.g., to a higher or even thehighest rate) in this situation for better results and productivity(e.g., an efficient software upgrade). In other embodiments a ratecontrol mechanism with very long memory may be used. For example, someembodiments employ a non-standard rate control mechanism that includesan extended expiry time for communication between the base station andthe power sensitive device. Further, in some embodiments, a differentretry mechanism with more aggressive fall back rate may be used. Forexample, in accordance with some embodiments, a different retrymechanism is implemented in which the power sensitive device 120 wakesup and does not perform any listening related operations before sendingthe one byte (e.g., the one number that the sensor is configured tosend). Not having the power sensitive device 120 be required to listenbefore sending saves on power consumption. Continuing with this example,if the power sensitive device 120 receives an ACK, then the transmissionwas successful. However, if not, the different retry mechanism attemptsa subsequent transmission of the number. It has been found that thelikelihood of the second (or retry) submission is high, because thepackets are short. When in the case it appears that the send is notsuccessful (e.g., after a predetermined number of retries), the powersensitive device can be configured to then engage in listeningoperations before sending the packet. In other words, the different ratemechanism can include operations of the standard retry mechanism, whichlistens before talking. Thus, using the different rate mechanism asdescribed above saves a lot of power.

It is known that aggregation is used to improve performance of 802.11,such that the frame header is not sent for every byte of data. It shouldbe noted that standard aggregation technology is not taught herein asone skilled in the art would readily understand standard aggregation ofpackets as it relates to 802.11. Aggregation of packets reduces overheadoperations and increases the throughput (TPUT). Although, aggregationdoes introduce some delay in the communication. In the presentdisclosure, because the packets of the power sensitive device 120 aretypically small, there is very little need for aggregation or, in somecases, no aggregate may be needed or used at all. For example,aggregation may not be useful for the low data rate application, becausethere is some overhead to set up the aggregation at the beginning stage.Further, there is very little to no need for handling the Block ACKmechanism, which is a mechanism for transmitting blocks of data framesfrom the originator to the recipient to improve MAC efficiency. BlockACK mechanisms are not taught herein as they are readily understood byone skilled in the art. Therefore, taking the above criteria intoconsideration and in accordance with some embodiments, the packetaggregation settings can be adjusted. The size of the packet aggregationshall be changed dynamically (e.g., near real-time and based on criteriaincluding present power state and current network traffic with the powersensitive device) by the AP 110 to reflect the power state and thecurrent network traffic with the power sensitive device that the deviceneeds to be supported. Thus, in some embodiments, for regular packetscontaining short packets, no aggregation is used or a small aggregationsize is used, where the small aggregation size corresponds to the shortpackets. For more data intensive items, such as data log dumps or datatrends, the AP 110 aggregation size may be increased by the AP 110. Forexample, the aggregation size may be increased to a mid-range size ornear mid-range size (e.g., a size that is between the shortest size tothe maximum size and that corresponds to the size of the packets). Forother situations, such as for firmware upgrades to the sensor, large orthe maximum aggregate size can be used. Further, when, at any time,there is a lot of data (e.g., for a firmware upgrade), then anegotiation can take place in real-time to negotiate aggregation size,in the manner discussed above. Moreover, it should be noted thatstandard aggregation in 802.11 typically creates a delay. For instance,after receiving a first packet, the receiving entity may wait apredetermined amount of time to determine whether a second (or more)packet(s) will arrive. That wait time is the delay. In accordance withthe present disclosure, because the AP and the power sensitive device120 can be configured to send sensor data right away, unless instructedto negotiate aggregation, then there is no delay, which also saves powerconsumption.

802.11 Synchronization Improvement for Saving Power Consumption and MacEfficiency

In accordance with some embodiments herein, power consumption can bereduced by improving synchronization. Various techniques for improvingsynchronization are discussed in detail below. In other words, theasynchronous nature of the network causes unnecessary power to beconsumed by the power sensitive device 120. It is known that 802.11 is aprotocol in a network where different APs are not synchronized. Clientssynchronize themselves by updating the clock. There is no time trackingphase lock loop (PLL)-like mechanism implemented. As a result there aretwo sets of problems, as follows. First, the power sensitive device 120is required to wake up to get the TSF timer from the AP 110. Second,when different APs are not synchronized and they coordinate, the resultis a MAC efficiency problem.

With regard to the first problem, as discussed above, waking up the mainprocessor 210 unnecessarily causes a power consumption penalty. This isbecause the client (e.g., the power sensitive device 120) needs to wakeup frequently to get the beacon to be synchronized which results inlarge power consumption. Also, presently, the client needs to wake upearlier than beacon to accommodate the client clock inaccuracy whichresult in even more power penalty. With regard to the second problem,different APs cannot coordinate and time share properly. They rely onEDCA and, thus, MAC efficiency is dropped. Different APs cannotcoordinate and time share properly and they rely on Enhanced DistributedChannel Access (EDCA) and MAC efficiency is dropped.

Various embodiments provide various improvement mechanisms for theclient-AP (e.g., power sensitive device 120-base station 110) case tosave power, as discussed below. Some embodiments employ, by the basestation, a synchronization mechanism before communicating with the powersensitive device, wherein the synchronization mechanism is characterizedat least by offloading a portion of processing tasks associated withsynchronization from the power sensitive device to the base station. Inother embodiments, a mechanism is provided where the client cancalculate the clock frequency offset between the AP and itself and doesself-correction for layer 2 and does not solely rely on updating theclock using TSF. This mechanism can be used to save power. In accordancewith another mechanism, for every packet that is transmitted from the APto the client, the clock frequency offset (CFO) is calculated at thebeginning of the packet and applied. The CFO from CFO calculation duringthe preamble can be used as way to learn (e.g., “see”) the crystaloffset. Pilots in packets may be used. Calculating the TSF offset overtime and tracking the trend may be used. A new packet exchange may beused to track the clock frequency and phase and perform compensationoperations. Synchronization from the 802.11 specification that is donefor localization may also be used to further improve client-APsynchronization.

One embodiment can be understood with reference to FIG. 7, a timingdiagram 700 for determining an estimate of the clock drift to use inreducing synchronization calculations for synching every exchange, tosave power. The client (e.g., camera) wakes up before the beacon toaccommodate an unsynchronized clock with the AP. The interval of timefrom when the camera wakes to when the beacon arrives is calculated andsaved as Δt₁. After a predetermined wait time for another beacon (itdoes not have to be the next, subsequent beacon), the interval of timefrom when the camera wakes to when the second beacon arrives iscalculated and saved as Δt₂. After at least two intervals are calculatedand saved, then the difference between those intervals (e.g., Δt₂−Δt₁)is calculated. It is the difference between these two differences of theearly wake up time to the arrival of the beacon, that is used to computean estimate of the camera's clock drift.

Another embodiment can be understood with reference to FIG. 8, aflowchart 800 illustrating a method for determining an estimate of thefrequency drift to use in reducing synchronization calculations forsynching every exchange, to save power. When the AP (e.g., the basestation 110) sends packets to a client (e.g., the camera), the APattempts to send the packets at some certain frequency. For example,assume that the AP is sending the packet to the client at 5850megahertz. But the client receives the packet at 5800 megahertz. Thus,the frequency drift is 50 kilohertz. This frequency drift can be used tofigure out how much clock drift the other side has, because the clockcomes from the oscillator. Once the oscillator drift is figured out, itcan be compensated for once, which saves power. An exemplary techniqueis discussed referring to FIG. 8. Once the frequency offset is known, itcan be applied to allow processing without recalculating the frequencyoffset for every packet. A margin of error (e.g., an offset threshold)is applied to account for the case when even the known frequency offsetmay be incorrect or drift for any reason. Thus, according to thistechnique, the frequency offset (e.g., an estimate of the frequencyoffset) is calculated (802) as discussed above. The technique determineswhether the calculated offset is greater than a predetermined threshold(804). If so, then the timer interrupt value is modified (810),accordingly, to account for the offset. The client goes into a differentstate and waits (812) until it's time to estimate the frequency offsetagain (802). When the calculated offset is not greater than thepredetermined threshold (806), then the timer interrupt value remainsthe same and the goes into a different state and waits (808) until it'stime to estimate the frequency offset again (802).

With regard to synchronization between different AP's, some embodimentsrecognize that synchronization between different APs may be used tobetter time share. Different APs can be synchronized usingsynchronization mechanisms that are defined for wired and wirelessnetworking. Examples of such synchronization mechanisms and theirrespective accuracies include:

IEEE 1588—Sub micro second;

GPS—Sub micro second;

TTP—Sub micro second;

NTP—Few millisecond; and

SERCOS—Sub micro second.

With regard to these synchronization protocols, the following is setforth: For IEEE 1588, the target is groups of relatively stablecomponents, locally networked (a few subnets), cooperating on a set ofwell-defined tasks. For NTP: (Network Time Protocol, RFC 1305), thetarget is autonomous systems widely dispersed on the Internet. For GPS:(Satellite based Global Positioning System of the US Department ofDefense), the target is autonomous, widely dispersed systems. ForTTP(www5ttpforumeorg), SERCOS (IEC 61491), the target is tightlyintegrated, usually bus or specialized TDMA network based closedsystems.

Accuracy can be further improved by listening to the packets of otherAPs and the respective calculated CFO between different APs. Also, insome embodiments, A different duration of synchronization technique onthe order of tens of milliseconds can be assigned, which cause MACefficiency to be greatly improved. It should be noted that thesemechanisms can be used for deployed mesh networks.

Present embodiments recognize that IEEE 1588 synchronization may be agood candidate for synchronizing client-AP communication. It should beappreciated that IEEE 1588 is a protocol designed to synchronizereal-time clocks in the nodes of a distributed system that communicateusing a sub microsecond network. For purposes of understanding, refer toFIG. 9, a high-level functional block diagram 900 illustrating IEEE 1588synchronization, which can be implemented by the base station 110 forexample. Also, one skilled in the art would readily recognize IEEE 1588synchronization, as depicted in FIG. 10, a diagram 1000 illustrating aprecision time protocol defined in IEEE 1588, which can be implementedby the base station 110 for example. Therefore, in some embodiments, byimproving synchronization, beacon reception time can be greatly reduced(e.g., almost of not exactly by half of its time according to prior artprocedures).

Accuracy can be further improved by listening to the packets of otherAPs and the respective calculated CFO between different APs. Also, insome embodiments, a different duration of synchronization technique onthe order of tens of milliseconds can be assigned, which cause MACefficiency to be greatly improved. It should be noted that thesemechanisms can be used for deployed mesh networks.

From the foregoing, it will be appreciated that specific embodiments ofthe invention have been described herein for purposes of illustration,but that various modifications may be made without deviating from thescope of the invention. Accordingly, the invention is not limited exceptas by the appended claims.

What is claimed is:
 1. A method for reducing power consumption of apower sensitive wireless device (“power sensitive device”) operating ina wireless local area network (WLAN) system, the method comprising:detecting, by a base station in the WLAN system, whether a portabledevice associated with a select user is within a predetermined physicalproximity to a user-defined geo-fence, wherein the user-definedgeo-fence is defined by a user specifying a geographic location of theuser-defined geo-fence; responsive to a result of the detecting alocation of the portable device associated with the select user,determining an appropriate power setting for the power sensitive device,wherein the portable device and the power sensitive device are differentdevices, and wherein the determining the appropriate power settingcomprises: decreasing the power setting when the select user is withinthe predetermined physical proximity to the user-defined geo-fence;increasing the power setting when the select user is outside thepredetermined physical proximity to the user-defined geo-fence; andtransmitting, via the WLAN system, an instruction to the power sensitivedevice, wherein the instruction causes the power sensitive device toapply the appropriate power setting.
 2. The method of claim 1, furthercomprising: receiving, from an application on the portable device of theselect user, an indication that the select user is within thepredetermined physical proximity to the user-defined geo-fence.
 3. Themethod of claim 1, wherein the detecting is based on an association ofthe portable device of the select user with the WLAN.
 4. The method ofclaim 1, wherein the detecting is based on a location of the select useras reported by a global positioning system (GPS) of the portable deviceof the select user.
 5. The method of claim 1, wherein the detecting isbased on a multicast discovery mechanism of the WLAN.
 6. The method ofclaim 1, wherein the detecting is based on cellular communicationinformation from the portable device of the select user.
 7. The methodof claim 1, wherein available power setting comprises any of: wirelesspower state; wireless wakeup period; sensory related settings; or mainprocessor settings.
 8. The method of claim 1, further comprising:changing a timing for a delivery traffic indication message (DTIM)specifically for the power sensitive device based on a delay requirementreceived from the power sensitive device.
 9. The method of claim 8,wherein the timing is changed further based on the result of thedetecting.
 10. The method of claim 1, further comprising: coordinatingwith the power sensitive device regarding operating in a wirelessnetwork management (WNM)-Sleep mode, as defined in IEEE 802.11 family ofstandards, based on the result of the detecting.
 11. The method of claim1, further comprising: responsive to the result of detecting, causingthe power sensitive device to change a frame rate and/or a compressionratio of a camera on the power sensitive device.
 12. The method of claim1, further comprising: responsive to the result of detecting, causingthe power sensitive device to change a motion detection sensitivity of amotion detection sensor on the power sensitive device.
 13. The method ofclaim 1, further comprising: responsive to the result of detecting,causing the power sensitive device to change a sampling frequency thatthe power sensitive device monitors of a passive infrared sensor. 14.The method of claim 1, further comprising: responsive to the result ofdetecting, causing the power sensitive device to change a number ofsensors that the power sensitive device monitors in an infrared sensorarray.
 15. The method of claim 1, further comprising: receiving, from anapplication on the portable device of the select user, a userinstruction to manually change the power setting of the power sensitivedevice.
 16. The method of claim 1, wherein the detecting includescommunicating with a remote server for receiving the location of theportable device of the select user.
 17. The method of claim 1, whereindetermining the appropriate power setting for the power sensitive devicefurther comprises: comparing a historic location of the portable deviceassociated with the select user to determine a motional status; andadjusting the appropriate power setting for the power sensitive devicebased on the motional status.
 18. The method of claim 17, wherein thepower setting includes: a first profile; a second profile, wherein powerconsumption is greater than the first profile; and a third profilewherein the power consumption is greater than the second profile. 19.The method of claim 17, wherein the power setting is any of arriving,dwelling, or leaving.
 20. The method of claim 1, further comprising:adopting modified IEEE 802.11 standards such that a dependency on beaconreception for maintaining connection with the power sensitive devicebecomes reduced or removed.
 21. The method of claim 1, furthercomprising: employing a compressed Internet Protocol (IP) header forcommunication between the power sensitive device and the base station.22. The method of claim 1, further comprising: offloading IP operationsfrom the power sensitive device to the base station so as to allow thepower sensitive device to avoid the IP operations.
 23. The method ofclaim 1, further comprising: employing, by the base station, anunscheduled beacon reception mechanism that causes the power sensitivedevice to wake up on an as-needed basis to receive a beacon.
 24. Themethod of claim 1, further comprising: customizing, by the base stationand specifically for the power sensitive device, downlink communicationfrom the base station to the power sensitive device, wherein thecustomizing includes adopting a non-standard timeout for the powersensitive device.
 25. The method of claim 1, further comprising:employing a non-standard rate control mechanism that includes anextended expiry time for communication between the base station and thepower sensitive device.
 26. The method of claim 1, further comprising:dynamically adjusting a size of packet aggregation based on a currentpower state of the power sensitive device and/or a characteristic ofcurrent network traffic with the power sensitive device.
 27. The methodof claim 1, further comprising: employing, by the base station, asynchronization mechanism before communicating with the power sensitivedevice, wherein the synchronization mechanism is characterized at leastby offloading a portion of processing tasks associated withsynchronization from the power sensitive device to the base station.